The pulse meter is a type of electric energy meter which is widely used, particularly in North America. Compared with the conversional 86 series electric meter, the pulse meter is improved by adding an electric pulse device, while maintaining the same installation size. However, the pulse output lead of the pulse meter, which uses a dedicated terminal junction box, may identify a power direction, output a forward direction pulse and a reverse direction pulse respectively, and output an active pulse and a passive pulse according to the use's requirement.
However, the communication distance of the pulse meter is relatively short, which is generally 200 meters, and thus it is difficult to meet the communication requirement between the electric meter and the consumer device. By using RS485, the communication distance of the pulse meter may reach about 1200 meters, thus significantly increasing the communication distance of the electric meter.
In order to increase the communication distance of the electric meter, the pulse communication may be converted into RS485 communication by PLC (Programmable Logic Controller) in the prior art. However, because the PLC is relatively expensive, the conventional way to convert the pulse communication into RS485 communication by PLC is high in cost, and thus it is difficult to popularize.